tee: tee_shm: Constify dma_buf_ops structures.

dma_buf_ops are not supposed to change at runtime. All functions
working with dma_buf_ops provided by <linux/dma-buf.h> work with
const dma_buf_ops. So mark the non-const structs as const.

File size before:
text data bss dec hex filename
2026 112 0 2138 85a drivers/tee/tee_shm.o

File size After adding 'const':
text data bss dec hex filename
2138 0 0 2138 85a drivers/tee/tee_shm.o

Signed-off-by: Arvind Yadav <[e-mail]>
Signed-off-by: Jens Wiklander <[e-mail]>

drivers/tee/tee_shm.c

···
 			       size, vma->vm_page_prot);
 }
 
-static struct dma_buf_ops tee_shm_dma_buf_ops = {
+static const struct dma_buf_ops tee_shm_dma_buf_ops = {
 	.map_dma_buf = tee_shm_op_map_dma_buf,
 	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
 	.release = tee_shm_op_release,